Method of using a surgical tissue retractor

ABSTRACT

A method of performing an operation, e.g. a spinal operation, on a patient using a retractor comprising a pair of blade assemblies which are adapted to open about a set of axes that are not parallel to a third spatial axis, and further comprising a pair of arms, which are adapted to move the pair of blade assemblies apart from one another in the third spatial axis. In the method, the blade assemblies are closed to assume a low profile, inserted into a relatively small incision, and stretched apart from each other, thereby stretching the skin about the incision to form an aperture longer than the incision. The blade assemblies are then opened by rotating the blades about the set of axes, stretching the skin around the incision in a second direction that is substantially perpendicular to the first direction (i.e. the direction of the incision.).

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 15/602,542, filed May 23, 2017, which is a continuation of U.S.patent application Ser. No. 15/204,329, filed Jul. 7, 2016, which is acontinuation of U.S. patent application Ser. No. 13/794,470, filed Mar.11, 2013. The contents U.S. patent application Ser. No. 13/794,470,filed Mar. 11, 2013 are hereby incorporated by reference in itsentirety.

FIELD OF THE INVENTION

The present invention relates to the field of surgery and moreparticularly to a retractor for use in inter alia surgery of the lowerback.

BACKGROUND OF THE INVENTION

Retractors are surgical devices used to spread bodily tissues in orderto allow a surgeon or surgical assistant to see and access a part of thebody that is to be surgically treated. In general, retractors comprise apair of jaws or blades that grip the bodily tissue and push it apartunder the force generated by an actuator, such as a pair of scissor-likearms having a distal end and a proximal end. The proximal end generallydefines a pair of handles and the distal end attaches to the pair ofblades so that manipulation of the handles causes the blades to moveapart from one another. Once an incision is made in the body to beoperated on, the blades are inserted into the incision and the actuatoris manipulated to move the blades of the retractor apart, thus spreadingthe tissue and providing an aperture through which the surgeon canaccess visualize the tissue to be surgically treated. One problem withthis type of retractor is that the aperture size is generally limited bythe size of the incision, meaning that a large aperture requires arelatively large incision. The drawback to this arrangement is thatlarger incisions result in the need for longer periods for healing ofthe incision. There is thus a need for a surgical retractor that iscapable of creating a relatively large aperture using a relatively smallincision, thereby reducing the invasiveness of the surgical procedure,post-operative healing times and patient discomfort.

SUMMARY

One embodiment comprises a system for creating an operative corridor ina human body, comprising: a probe, wherein the probe is configured to beplaced through the tissues of a patient from the surface of the tissueto a location of interest; a retractor system, wherein the retractorsystem comprises retractor blades having an internal space, wherein theinternal space is substantially the same shape as the probe such thatthe internal space will slip over the probe when the probe is insertedinto the tissues of the patient.

Another embodiment comprises a method of accessing a spine. The methodincludes forming an incision in tissue; placing a probe into theincision; engaging an end of the probe with an intervertebral discspace; positioning a mating retractor blade system over the probe;sliding the mating retractor blade system down and over the length ofthe probe; and activating the mating retractor blade system to open themating retractor blade system to create an operative corridor.

Another embodiment comprises a method of accessing a surgery site thatincludes forming an incision in tissue; placing a probe into theincision; anchoring an end of the probe at the surgery site; positioninga mating retractor blade system over the probe; sliding the matingretractor blade system down the length of the probe; and activating themating retractor blade system to open the mating retractor blade systemto create an operative corridor.

Another embodiment comprises a method of accessing a human spine thatincludes forming an incision in tissue; inserting an endoscope into theincision, wherein the endoscope is configured to allow safe navigationto the spine; sliding a mating retractor system in a close configurationover the endoscope; sliding the mating retractor system down and over atleast a portion of the endoscope into the incision in tissue; andactivating the mating retractor system to create an operative corridorin the tissue.

Another embodiment comprise a retractor that includes a first bladeassembly comprising a first blade rotatable about a first axis, a secondblade rotatable about said first axis and an adjuster in mechanicalcommunication with the first and second blades and adapted to rotate thefirst and second blades relative to each other about said first axis. Asecond blade assembly includes at least a third blade rotatable about asecond axis and optionally a fourth blade rotatable about said secondaxis and, when said fourth blade is present in said second bladeassembly. An adjuster is in mechanical communication with the third andfourth blades and adapted to rotate the third and fourth blades relativeto each other about said second axis, wherein said second axis isdifferent from said first axis. The retractor also includes means formoving said first blade assembly relative to said second blade assemblyalong a third axis that is not parallel to said first and second axes,wherein the first blade assembly moves while the second blade assemblyremains substantially stationary.

Another embodiment comprises a retractor that includes a first bladeassembly comprising a first blade rotatable about a first axis, a fixedsecond blade and an adjuster in mechanical communication with the firstand second blades and adapted to rotate the first and second bladesrelative to each other about said first axis; a second blade assemblycomprising at least a third blade rotatable about a second axis whereinsaid second axis is different from said first axis; and wherein saidfirst blade assembly is movable relative to said second blade assemblyalong a third axis that is not parallel to said first and second axes;wherein said first blade assembly is configured to detachably separatefrom said second blade assembly when said retractor is in an openconfiguration.

In certain embodiments, the retractor (surgical retractor) can comprise(a) a first blade assembly comprising a first blade rotatable about afirst axis, a second blade rotatable about said first axis and anadjuster in mechanical communication with the first and second bladesand adapted to rotate the first and second blades relative to each otherabout said first axis; (b) a second blade assembly comprising at least athird blade rotatable about a second axis and optionally a fourth bladerotatable about said second axis and, when said fourth blade is presentin said second blade assembly, an adjuster in mechanical communicationwith the third and fourth blades and adapted to rotate the third andfourth blades relative to each other about said second axis, whereinsaid second axis is different from said first axis; and (c) a means formoving said first blade assembly relative to said second blade assemblyalong a third axis that is not parallel to said first and second axes.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIG. 1 provides a perspective view of a retractor with a pair of bladeassemblies in a closed and parallel configuration.

FIG. 2 provides a perspective view of a retractor, this time with theblades open in one direction along directional arrows c and d. Openingthe retractor in this direction stretches the incision along its length.

FIG. 3 provides a perspective view of a retractor, now with the twoblade assemblies open in separate directions from the first direction ofopening. Opening the retractor blade assemblies stretches the incisionopen in a second direction that is different from, and essentially notparallel to, the first direction.

FIGS. 4, 5 and 6 provide exploded perspective views of a retractor, thehandles being separated from the arm assembly and the blade assembliesbeing separated from the arm assembly.

FIGS. 7, 8 and 9 provide top views of the retractor.

FIGS. 10 and 11 provide close-up views of a blade.

FIG. 12 provides a perspective view of an arm assembly.

FIGS. 13-19 provide exploded views of a blade assembly, from which theassembly and operation of the blade assembly can be discerned.

FIGS. 23-25 show side views of a first blade of a blade assembly, whileFIGS. 26-28 show side views of a second blade of a blade assembly.

FIGS. 20-22 show various blades that may be employed in bladeassemblies.

FIGS. 29-30 show side views of barrels of blade assemblies.

FIGS. 30 and 31 show the relationship between the angles of slots in thefirst blade and the second blade of the blade assembly.

FIGS. 32-35 show perspective views of a retractor of the invention inoperation. A surgeon makes an incision having length L, into which theclosed blade assemblies of the retractor are inserted. The surgeon thenopens the retractor to create a lengthwise opening having length L′,wherein L′>L. Finally the surgeon opens the blade assemblies to create aL′×W′ aperture. In some embodiments, the handles 24, 44 can be removedfrom the arm assembly to permit the surgeon even greater ability to seeand operate on the tissue to be treated.

FIGS. 36A-36F show the use of a probe to insert a retractor system toform an operative channel through the tissue of a patient to access aportion of the patient's spine.

FIGS. 37A-37D show various embodiments of a probe system which can beused to insert a retractor system to form an operative channel throughthe tissue of a patient.

FIGS. 38A-38I show various cross sections of a probe system.

DETAILED DESCRIPTION OF THE INVENTION

The retractor embodiments described herein provides advantages over theprior art retractors comprising a set of blades and an actuator, such asa set of scissor arms. Additional details of these embodiments can befound in U.S. Pat. No. 8,142,355 (issued on Mar. 27, 2012), which ishereby incorporated in its entirety herein. The retractor embodimentsdescribed herein can allowed the person skilled in the art to insert arelatively compact set of retractor blades into an incision having ashort length. In some embodiments, the compact set of retractor bladesare of such a size that they can be inserted within the incision so thatthey are snugly embraced by the side walls of the incision. Activationof an actuator causes the blades to move apart in a direction that isessentially parallel to the length of the incision. This causes thetissue to stretch in one direction, creating an opening having a lengthin that direction that is substantially longer than the incision. Oncethe retractor is opened in the first direction, the actuator may belocked open. Then a pair of adjusters on the blade assemblies may bemanipulated to open the blade assemblies, thus pulling the incisedtissue apart in directions that are not parallel to the incision. Insome embodiments, these directions may be perpendicular, substantiallyperpendicular or oblique to the incision. Thus there is opened up anaperture that is substantially longer than the incision, and thus issubstantially larger than would be possible using a prior art device.Thus in relative terms, the surgeon may use a smaller incision, and insome cases a much smaller incision, than would have been required with aprior art device. Moreover, removal of the retractor, e.g. by closingthe blade assemblies, replacing the handles (if necessary), closing thearm assembly and removing the blade assemblies from the incision, causesthe incision to relax back to a size that is much smaller than wouldhave resulted from use of the prior art retractor.

In some embodiments, the handles, the blade assemblies or both areremovable. In some embodiments, the blades of the blade assemblies maytake on a variety of shapes and sizes. In some embodiments, a kit caninclude a plurality of retractors having blades of various sizes, shapesor both. In some embodiments, the kit comprises one or more sets ofhandles, one or more arm assemblies and two or more blade assemblies(optionally of varying blade sizes and/or shapes). In some embodiments,a kit includes a retractor of as described herein optionally more thantwo blades, at least two of which differ from one another in size, shapeor both, and one or more pedicle screws for performing lumbar surgery.Thus, the embodiments described herein provides a retractor, a varietyof surgical kits for performing surgery, especially back surgery, andmethods of using the retractor to perform surgery, and especially backsurgery.

The foregoing and further needs are met by embodiments, which provide(a) a retractor comprising: (a) a first blade assembly comprising afirst blade rotatable about a first axis, a second blade rotatable aboutsaid first axis and an adjuster in mechanical communication with thefirst and second blades and adapted to rotate the first and secondblades relative to each other about said first axis; (b) a second bladeassembly comprising at least a third blade rotatable about a second axisand optionally a fourth blade rotatable about said second axis and, whensaid fourth blade is present in said second blade assembly, an adjusterin mechanical communication with the third and fourth blades and adaptedto rotate the third and fourth blades relative to each other about saidsecond axis, wherein said second axis is different from said first axis;and (c) a means for moving said first blade assembly relative to saidsecond blade assembly along a third axis that is not parallel to saidfirst and second axes. It is to be understood by one of ordinary skillin the art that, while at present a preferred embodiment uses a meansfor moving said first blade assembly relative to said second bladeassembly employs two arms that are held parallel to one another by ameans for stabilizing the arms, it is also possible for said means formoving said first blade assembly relative to said second blade assemblyto be a pair of crossing arms joined to one another at a pivot point. Insuch cases, the blade assemblies move relative to one another along anarc. Nonetheless, their general direction of motion relative to oneanother, and the direction of motion that is of especial interest in thecontext of the present application, is along an axis that is generallydefined by a line passing through the blade assemblies, e.g. at thepoint where each blade assembly is attached to its respective arm. Inparticular embodiments, the second blade assembly comprises a thirdblade, a fourth blade and an adjuster in mechanical communication withthe third and fourth blades and adapted to rotate the third and fourthblades relative to each other about said second axis. In some suchembodiments, the first and second axes may be substantially coplanarwith one another. Indeed in some currently preferred embodiments, thefirst and second axes are not only coplanar but also substantiallyparallel to one another. In particular embodiments, the first and secondaxes are coplanar with, parallel to, or at some pre-determined skewangle with respect to one another. In some specific examples, the thirdaxis is substantially perpendicular to the first axis, the second axisor both the first and second axes. In particular embodiments, the thirdaxis is substantially perpendicular to both the first axis and thesecond axis. In some embodiments, the third axis is perpendicular to thefirst axis, the second axis or both the first and second axes. In somespecific embodiments, the third axis is perpendicular to both the firstand second axes. In some embodiments, the retractor described hereinpossesses a means for locking said first and second blade assemblies inat least one predetermined position along said second axis. In someparticular embodiments, two of said blades are of substantiallydifferent sizes in at least one dimension. In some specific embodiments,at least two blades of different sizes form part of the same bladeassembly, while in other embodiments, two blades of different sizes formparts of different blade assemblies. In some particular embodiments, atleast one of the first, second, third and, when present, forth blades isa comb-shaped blade. In some embodiments, at least one of the first,second, third and, when present, fourth blades is a substantially flatblade. In some embodiments, Some embodiments include at least oneremovable blade assembly. In some specific embodiments, both bladeassemblies are removable.

In some embodiments, a method (e.g. a method of surgery—in particularspinal surgery, e.g. in the lumbar region of the back) comprises thesteps of: (a) providing a retractor comprising: (i) a first bladeassembly comprising a first blade rotatable about a first axis, a secondblade rotatable about said first axis and an adjuster in mechanicalcommunication with the first and second blades and adapted to rotate thefirst and second blades relative to each other about said first axis;(ii) a second blade assembly comprising at least a third blade rotatableabout a second axis and optionally a fourth blade rotatable about saidsecond axis and, when said fourth blade is present in said second bladeassembly, an adjuster in mechanical communication with the third andfourth blades and adapted to rotate the third and fourth blades relativeto each other about said second axis, wherein said second axis isdifferent from said first axis; and (iii) a means for moving said firstblade assembly relative to said second blade assembly along a third axisthat is not parallel to said first and second axes; (b) adjusting thefirst and second blades of the first blade assembly to be substantiallyparallel to each other to form a first closed blade assembly; (c)adjusting the third blade, and when present the fourth blade, of thesecond blade assembly to be substantially parallel to the first andsecond blades of the first blade assembly; (d) making an incision in atissue of a body; (e) inserting said first blade assembly and saidsecond blade assembly within the incision; (f) moving the first bladeassembly away from the second blade assembly along said third axis andalong the length of the incision so that the incision is stretched tocreate an opening longer than the incision; and (g) adjusting the firstand second blades of the first blade assembly about said first axis toan open position, and, when said fourth blade of said second bladeassembly is present, adjusting the third and fourth blades of the secondblade assembly substantially about said second axis to an open position,thereby stretching the incision out from said third axis and creating anaperture in the tissue that is longer and wider than the incision. Insome such embodiments, the second blade assembly comprises a thirdblade, a fourth blade and an adjuster in mechanical communication withthe third and fourth blades and adapted to rotate the third and fourthblades relative to each other about said second axis. In some particularembodiments, the first and second axes are substantially coplanar withone another, substantially parallel to one another and/or substantiallyperpendicular to the third axis. The third axis is the line passingthrough the points at which the blade assemblies are joined to the armsof the retractor. As mentioned above, the person skilled in the art willrecognize that when the arms are scissor-like arms that cross oneanother and are joined at a pivot point, the motion of the bladeassemblies with respect to one another will trace out an arc. However,the direction of motion of the two blade assemblies with respect to oneanother will be essentially along the third axis. In any case, inparticular embodiments, the first and second axes are coplanar with oneanother, parallel to one another and/or perpendicular to the third axis.In particular embodiments, the third axis is perpendicular to the firstaxis, the second axis or both the first and second axes. In someparticular embodiments, the third axis is perpendicular to both thefirst and second axes. In some embodiments, at least two of said bladesare of substantially different sizes in at least one dimension (e.g.length, width or both). In some specific embodiments, said two blades ofdifferent sizes form part of the same blade assembly. In other specificembodiments, said two blades of different sizes form parts of differentblade assemblies. In some embodiments, at least one of the first,second, third and, when present, fourth blades is a comb-shaped blade.In some embodiments, at least one of the first, second, third and, whenpresent, fourth blades is a substantially flat blade. In someembodiments, the retractor further comprise a means for locking saidfirst blade assembly and second blade assembly in a position apart fromeach other along said second axis. In some embodiments, the methodfurther comprises removing at least a part of said means for moving thefirst and second blade assemblies toward and away from each other alongthe second axis. In some embodiments, the incision is made in the lumbarregion of the back near the spine. In some embodiments, the methodfurther comprises placing one or more pedicle screws in the spine of thebody. In other embodiments, the method further comprises adjusting thefirst and second blade assemblies to closed positions and removing theretractor from the incision, thereby returning the incision tosubstantially the same shape and size as prior to retractor insertion.In still further embodiments, at least one blade assembly is removable.In specific embodiments, both blade assemblies are removable.

In some embodiments, a kit for performing an operation, includes: (a) aretractor comprising: (i) a first blade assembly comprising a firstblade rotatable about a first axis, a second blade rotatable about saidfirst axis and an adjuster in mechanical communication with the firstand second blades and adapted to rotate the first and second bladesrelative to each other about said first axis; (ii) a second bladeassembly comprising at least a third blade rotatable about a second axisand optionally a fourth blade rotatable about said second axis and, whensaid fourth blade is present in said second blade assembly, an adjusterin mechanical communication with the third and fourth blades and adaptedto rotate the third and fourth blades relative to each other about saidsecond axis, wherein said second axis is different from said first axis;and (iii) a means for moving said first blade assembly relative to saidsecond blade assembly along a third axis that is not parallel to saidfirst and second axes; and (b) at least one member of the groupconsisting of instructions for using the retractor to perform a surgicaloperation, scalpels, suture needles, pedicle screws, suture material,spinal implant material, spinal fusion rods, biocompatible adhesive andclosure staples. In some embodiments, the second blade assembly of theretractor comprises a third blade, a fourth blade and an adjuster inmechanical communication with the third and fourth blades and adapted torotate the third and fourth blades relative to each other about saidsecond axis. In some embodiments, the first and second axes aresubstantially coplanar with one another. In specific embodiments, thefirst and second axes are coplanar with one another. In someembodiments, the third axis is substantially perpendicular to the firstaxis, the second axis or both the first and second axes. In someembodiments, the third axis is substantially perpendicular to both thefirst axis and the second axis. In some embodiments, the third axis isperpendicular to the first axis, the second axis or both the first andsecond axes. In some embodiments, the third axis is perpendicular toboth the first and second axes. In some embodiments, the retractorfurther comprises a means for locking said first and second bladeassemblies in at least one predetermined position along said secondaxis. In some embodiments, two of said blades are of substantiallydifferent sizes in at least one dimension. In particular embodiments,two blades of different sizes form part of the same blade assembly. Insome embodiments, two blades of different sizes form parts of differentblade assemblies. In some embodiments, at least one of the first,second, third and, when present, forth blades is a comb-shaped blade. Insome embodiments, at least one of the first, second, third and, whenpresent, fourth blades is a substantially flat blade. In someembodiments, at least one blade assembly is removable. In some specificembodiments, both blade assemblies are removable.

In some embodiments, a retractor comprises: (a) a first arm having adistal end and a proximal end; (b) a second arm having a distal end anda proximal end; (c) a first blade assembly, attached near the distal endof the first arm and comprising a first blade, a second blade and anadjuster in mechanical communication with the first and second bladesand adapted to rotate the first and second blades relative to each otherabout a first axis; (d) a second blade assembly attached near the distalend of the second arm and comprising at least a third blade rotatableabout a second axis, optionally a fourth blade, and when the fourthblade is present, an adjuster in mechanical communication with the thirdand fourth blades and adapted to rotate the third and fourth bladesrelative to each other about said second axis; and (e) an actuatoradapted to move at least the distal ends of said first and second armsrelative to each other along a third axis that is not parallel to thefirst and second axes. In some embodiments of the retractor, the secondblade assembly comprises a third blade, a fourth blade and an adjusterin mechanical communication with the third and fourth blades and adaptedto rotate the third and fourth blades relative to each other about saidsecond axis. In some embodiments, the first and second axes aresubstantially coplanar with one another. In some embodiments, the firstand second axes are coplanar with one another. In some embodiments, thethird axis is substantially perpendicular to the first axis, the secondaxis or both the first and second axes. In some embodiments, the thirdaxis is substantially perpendicular to both the first axis and thesecond axis. In some embodiments, the third axis is perpendicular to thefirst axis, the second axis or both the first and second axes. In someembodiments, the third axis is perpendicular to both the first andsecond axes. In some embodiments, the retractor further comprises ameans for locking said first and second blade assemblies in at least onepredetermined position along said second axis. In some embodiments, atleast two of said blades are of substantially different sizes in atleast one dimension (e.g. length, width or both). In some embodiments,two blades of different sizes form part of the same blade assembly. Insome embodiments, two blades of different sizes form parts of differentblade assemblies. In some embodiments, at least one of the first,second, third and, when present, forth blades is a comb-shaped blade. Insome embodiments, at least one of the first, second, third and, whenpresent, fourth blades is a substantially flat blade. In someembodiments, at least one blade assembly is removable. In someembodiments, both blade assemblies are removable. In some embodiments,the actuator comprises a stabilizer which maintains at least a portionof each of the first and second arms in an attitude substantiallyparallel to each other when the first and second arms are moved towardand away from each other. In some embodiments, the stabilizing membercomprises a first crosspiece having first and second ends, a secondcrosspiece having third and fourth ends, the first and secondcrosspieces being connected to each other by a pivot, the first end ofthe first crosspiece being connected to the first arm by a pivot, thesecond end of the first crosspiece being slidably connected to thesecond arm, the third end of the second crosspiece being connected tothe second arm by a pivot and the fourth end of the second crosspiecebeing slidably connected to the first arm. In some specific embodiments,the first end of the first crosspiece is connected to the first arm at aposition distal to the slidable connection of the fourth end of thesecond crosspiece to the first arm. In some more specific embodiments,the third end of the second crosspiece is connected to the second arm ata position distal to the slidable connection of the second end of thefirst crosspiece to the second arm. In some embodiments, the retractorfurther comprises a lock adapted to reversibly hold said first andsecond arms apart from each other along the second axis. In somespecific embodiments, the lock is a ratchet lock comprising a ratchetblade and a ratchet release. In some more specific embodiments, theratchet lock holds the first arm and the second arm apart from eachother along the second axis. In some embodiments, the actuator comprisesa first handle connected to the proximal end of the first arm and asecond handle connected to the proximal end of the second handle,wherein the first handle and the second handle are adapted to move thedistal ends of the first and second arms toward and away from each otheralong the second axis. In some specific embodiments, the first andsecond handles are connected by a pivot. In some additional embodiments,the actuator further comprises a biasing member adapted to bias theactuator toward a preselected condition. In some specific embodiments,the biasing member is a biasing spring. In some embodiments, the biasingspring biases the distal ends of the first and second arms toward eachother.

In some embodiments, a method (e.g. a surgical method for surgery on thespine, e.g. the lumbar region of the spine) includes the steps of: (a)providing a retractor comprising: (i) a first arm having a distal endand a proximal end; (ii) a second arm having a distal end and a proximalend; (iii) a first blade assembly, attached near the distal end of thefirst arm and comprising a first blade, a second blade and an adjusterin mechanical communication with the first and second blades and adaptedto rotate the first and second blades relative to each other about afirst axis; (iv) a second blade assembly attached near the distal end ofthe second arm and comprising at least a third blade rotatable about asecond axis, optionally a fourth blade, and when the fourth blade ispresent, an adjuster in mechanical communication with the third andfourth blades and adapted to rotate the third and fourth blades relativeto each other about said second axis; and (v) an actuator adapted tomove at least the distal ends of said first and second arms relative toeach other along a third axis that is not parallel to the first andsecond axes; (b) ensuring that the first and second blades of the firstblade assembly are substantially parallel to each other to form a firstclosed blade assembly; (c) ensuring that the third blade, and whenpresent the fourth blade, of the second blade assembly are substantiallyparallel to the first and second blades of the first blade assembly; (d)making an incision in a tissue of a body; (e) inserting said first bladeassembly and said second blade assembly within the incision; (f)actuating the retractor such that said first blade assembly and secondblade assembly are moved apart from one another along the second axisand the incision is stretched along the length of the incision to createan opening longer than the incision; and (g) adjusting the first andsecond blades of the first blade assembly along said first axis to anopen position, and, when said fourth blade of said second blade assemblyis present, adjusting the third and fourth blades of the second bladeassembly substantially along said second axis to an open position,thereby stretching the incision along the first axis and creating anaperture in the tissue that is longer and wider than the incision. Insome embodiments, the method optionally comprises adjusting the thirdand fourth blades of the second blade assembly to an open position. Insome embodiments, the actuator comprises a means for locking the firstand second arms in a position apart from each other along the secondaxis, wherein the method further comprises locking said first and secondarms in a position apart from each other along the second axis. In someembodiments, the actuator further comprises a set of removable handles,the method optionally further comprising removing said set of removablehandles from the first and second arms. In other embodiments, theincision is made in the lumbar region of the back near the spine. Infurther embodiments, the method further comprises placing one or morepedicle screws in the spine of the body. In some embodiments the methodfurther comprises closing the first and second blade assemblies andremoving the retractor from the incision, thereby returning the incisionto substantially the same shape and size as prior to retractorinsertion.

In some embodiments, a kit (e.g. a surgical kit, especially a spinalsurgery kit, and most particularly a spinal surgery kit for surgery onthe lumbar region of the spine. In some embodiments, the kit comprises:(a) a retractor comprising: (i) a first arm having a distal end and aproximal end; (ii) a second arm having a distal end and a proximal end;(iii) a first blade assembly, attached near the distal end of the firstarm and comprising a first blade, a second blade and an adjuster inmechanical communication with the first and second blades and adapted torotate the first and second blades relative to each other about a firstaxis; (iv) a second blade assembly attached near the distal end of thesecond arm and comprising at least a third blade rotatable about asecond axis, optionally a fourth blade, and when the fourth blade ispresent, an adjuster in mechanical communication with the third andfourth blades and adapted to rotate the third and fourth blades relativeto each other about said second axis; and (v) an actuator adapted tomove at least the distal ends of said first and second arms relative toeach other along a third axis that is not parallel to the first andsecond axes; and (b) at least one member of the group consisting ofinstructions for using the retractor to perform a surgical operation,scalpels, suture needles, pedicle screws, suture material, spinalimplant material, spinal fusion rods, biocompatible adhesive and closurestaples. In some embodiments, the second blade assembly comprises athird blade, a fourth blade and an adjuster in mechanical communicationwith the third and fourth blades and adapted to rotate the third andfourth blades relative to each other about said second axis. In someembodiments, the first and second axes are substantially coplanar withone another. In some embodiments, the first and second axes are coplanarwith one another. In some embodiments, the third axis is substantiallyperpendicular to the first axis, the second axis or both the first andsecond axes. In some specific embodiments, the third axis issubstantially perpendicular to both the first axis and the second axis.In some embodiments, the third axis is perpendicular to the first axis,the second axis or both the first and second axes. In some embodiments,the third axis is perpendicular to both the first and second axes. Insome embodiments, the retractor further comprises a means for lockingsaid first and second blade assemblies in at least one predeterminedposition along said second axis. In some embodiments, two of said bladesare of substantially different sizes in at least one dimension. In someembodiments, at least two blades of different sizes form part of thesame blade assembly. In some specific embodiments, two blades ofdifferent sizes form parts of different blade assemblies. In some otherembodiments, at least one of the first, second, third and, when present,forth blades is a comb-shaped blade. In some embodiments, at least oneof the first, second, third and, when present, fourth blades is asubstantially flat blade. In some embodiments, at least one bladeassembly is removable. In some specific embodiments, both bladeassemblies are removable. In some embodiments, the actuator comprises astabilizer which maintains at least a portion of each of the first andsecond arms in an attitude substantially parallel to each other when thefirst and second arms are moved toward and away from each other. In somespecific embodiments, the stabilizing member comprises a firstcrosspiece having first and second ends, a second crosspiece havingthird and fourth ends, the first and second crosspieces being connectedto each other by a pivot, the first end of the first crosspiece beingconnected to the first arm by a pivot, the second end of the firstcrosspiece being slidably connected to the second arm, the third end ofthe second crosspiece being connected to the second arm by a pivot andthe fourth end of the second crosspiece being slidably connected to thefirst arm. In some embodiments, the first end of the first crosspiece isconnected to the first arm at a position distal to the slidableconnection of the fourth end of the second crosspiece to the first arm.In some embodiments, the third end of the second crosspiece is connectedto the second arm at a position distal to the slidable connection of thesecond end of the first crosspiece to the second arm. In someembodiments, the retractor further comprises a lock adapted toreversibly hold said first and second arms apart from each other alongthe second axis. In some specific embodiments, the lock is a ratchetlock comprising a ratchet blade and a ratchet release. In some morespecific embodiments, the ratchet lock holds the first arm and thesecond arm apart from each other along the second axis. In someembodiments, the actuator comprises a first handle connected to theproximal end of the first arm and a second handle connected to theproximal end of the second handle, wherein the first handle and thesecond handle are adapted to move the distal ends of the first andsecond arms toward and away from each other along the second axis. Insome embodiments, the first and second handles are connected by a pivot.In some embodiments, the actuator further comprises a biasing memberadapted to bias the actuator toward a preselected condition. In someembodiments, the biasing member is a biasing spring. In some specificembodiments, the biasing spring biases the distal ends of the first andsecond arms toward each other.

In some embodiments, a retractor includes: (a) a first arm having adistal end and a proximal end; (b) a second arm having a distal end anda proximal end, at least said distal end of said first arm and saiddistal end of said second arm being movable toward and away from eachother; (c) a first blade assembly attached near the distal end of thefirst arm, which comprises a first blade, a second blade and a means formoving said first and second blades relative to each other about a firstaxis to adopt at least an opened position and a closed position; (d) asecond blade assembly attached near the distal end of the second arm,which comprises a third blade, a fourth blade and a means for movingsaid third and fourth blades relative to each other about a second axisdifferent from said first axis; and (e) a means for moving at least saiddistal end of said first arm and said distal end of said second armrelative to one another along a third axis that is not parallel to saidfirst and second axes. In some embodiments, the first and second axesare substantially coplanar with one another. In some specificembodiments, the first and second axes are coplanar with one another. Insome embodiments, the third axis is substantially perpendicular to thefirst axis, the second axis or both the first and second axes. In someembodiments, the third axis is substantially perpendicular to both thefirst axis and the second axis. In some embodiments, the third axis isperpendicular to the first axis, the second axis or both the first andsecond axes. In some specific embodiments, the third axis isperpendicular to both the first and second axes. In some embodiments,the retractor further comprises a means for locking said first andsecond blade assemblies in at least one predetermined position alongsaid second axis. In some embodiments, two of said blades are ofsubstantially different sizes in at least one dimension. In someembodiments, two blades of different sizes form part of the same bladeassembly. In some embodiments, two blades of different sizes form partsof different blade assemblies. In some embodiments, at least one of thefirst, second, third and, when present, forth blades is a comb-shapedblade. In some embodiments, at least one of the first, second, thirdand, when present, fourth blades is a substantially flat blade. In someembodiments, at least one blade assembly is removable. In someembodiments, both blade assemblies are removable. In some embodiments,the means for moving at least said distal end of said first arm and saiddistal end of said second arm relative to one another along the secondaxis comprises a means for maintaining at least a portion of each of thefirst and second arms in an attitude substantially parallel to eachother when the first and second arms are moved toward and away from eachother. In some embodiments, the retractor further comprises a means forlocking the first and second arms in at least one preselected position.In some embodiments, the means for moving at least said distal end ofsaid first arm and said distal end of said second arm toward along saidthird axis comprises a removable means for moving said first arm andsaid second arm relative to each other along the second axis. In someembodiments, the removable means for moving said first arm and saidsecond arm toward and away from each other further comprises a means forbiasing the arms toward or away from each other.

In some embodiments, a method (e.g. a method of surgery, such as spinalsurgery, and in particular spinal surgery in the lumbar region of theback) includes the steps of: (a) providing a retractor comprising: (i) afirst arm having a distal end and a proximal end; (ii) a second armhaving a distal end and a proximal end, at least said distal end of saidsecond arm and said distal end of said second arm being movable towardand away from each other; (iii) a first blade assembly attached near thedistal end of the first arm, which comprises a first blade, a secondblade and a means for moving said first and second blades relative toeach other along a first axis to adopt at least an opened position and aclosed position; (iv) a second blade assembly attached near the distalend of the second arm, which comprises a third blade, a fourth blade anda means for moving said third and fourth blades relative to each othersubstantially along the first axis to adopt at least an opened positionand a closed position; and (v) a means for moving at least said distalend of said first arm and said distal end of said second arm relative toone another along a second axis; (b) ensuring that the first and secondblades of the first blade assembly are substantially parallel to eachother; (c) ensuring that the third and fourth blades of the second bladeassembly are substantially parallel to each other and to the first andsecond blades of the first blade assembly; (d) making an incision in atissue of a body; (e) inserting said first blade assembly and saidsecond blade assembly within the incision; (f) actuating the retractorsuch that said first blade assembly and second blade assembly are movedapart from one another along the second axis and the incision isstretched along the length of the incision to create an opening longerthan the incision; and (g) adjusting the first and second blades of thefirst blade assembly along said first axis to an open position, and,when said fourth blade of said second blade assembly is present,adjusting the third and fourth blades of the second blade assemblysubstantially along said second axis to an open position, therebystretching the incision along the first axis and creating an aperture inthe tissue that is longer and wider than the incision. In someembodiments, the actuator comprises a means for locking the first andsecond arms in a position apart from each other along the second axis,the method optionally further comprising locking said first and secondarms in a position apart from each other. In some embodiments, theactuator further comprises a set of removable handles, optionallyfurther comprising removing said set of removable handles from the firstand second arms. In some embodiments, the incision is made in the lumbarregion of the back near the spine. In some embodiments, the methodfurther comprises placing one or more pedicle screws in the spine of thebody. In some embodiments, the method further comprises closing thefirst and second blade assemblies and removing the retractor from theincision, thereby returning the incision to substantially the same shapeand size as prior to retractor insertion.

The in some arrangements a kit can include (a) a retractor comprising:(i) a first arm having a distal end and a proximal end; (ii) a secondarm having a distal end and a proximal end, at least said distal end ofsaid first arm and said distal end of said second arm being movabletoward and away from each other; (iii) a first blade assembly attachednear the distal end of the first arm, which comprises a first blade, asecond blade and a means for moving said first and second bladesrelative to each other along a first axis to adopt at least an openedposition and a closed position; (iv) a second blade assembly attachednear the distal end of the second arm, which comprises a third blade, afourth blade and a means for moving said third and fourth bladesrelative to each other substantially along the first axis to adopt atleast an opened position and a closed position; and (v) a means formoving at least said distal end of said first arm and said distal end ofsaid second arm relative to one another along a second axis; and (b) atleast one member of the group consisting of instructions for using theretractor to perform a surgical operation, scalpels, suture needles,pedicle screws, suture material, spinal implant material, spinal fusionrods, biocompatible adhesive and closure staples. In some embodiments,the first and second axes are substantially coplanar with one another.In some embodiments, the first and second axes are coplanar with oneanother. In some embodiments, the third axis is substantiallyperpendicular to the first axis, the second axis or both the first andsecond axes. In some embodiments, the third axis is substantiallyperpendicular to both the first axis and the second axis. In someembodiments, the third axis is perpendicular to the first axis, thesecond axis or both the first and second axes. In some embodiments, thethird axis is perpendicular to both the first and second axes. In someembodiments, the retractor of the kit further comprises a means forlocking said first and second blade assemblies in at least onepredetermined position along said second axis. In some embodiments, atleast two of said blades are of substantially different sizes in atleast one dimension. In some embodiments, at least two blades ofdifferent sizes form part of the same blade assembly. In someembodiments, two blades of different sizes form parts of different bladeassemblies. In some embodiments, at least one of the first, second,third and, when present, forth blades is a comb-shaped blade. In someembodiments, at least one of the first, second, third and, when present,fourth blades is a substantially flat blade. In some embodiments, atleast one blade assembly is removable. In some embodiments, both bladeassemblies are removable. In some embodiments, the means for moving atleast said distal end of said first arm and said distal end of saidsecond arm relative to one another along the second axis comprises ameans for maintaining at least a portion of each of the first and secondarms in an attitude substantially parallel to each other when the firstand second arms are moved toward and away from each other. In someembodiments, the retractor of the kit further comprises a means forlocking the first and second arms in at least one preselected position.In some embodiments, the means for moving at least said distal end ofsaid first arm and said distal end of said second arm toward along saidthird axis comprises a removable means for moving said first arm andsaid second arm relative to each other along the second axis. In someembodiments, the removable means for moving said first arm and saidsecond arm toward and away from each other further comprises a means forbiasing the arms toward or away from each other.

In some embodiments, a retractor blade assembly, includes: (a) a firstblade having attached thereto a first barrel, the first barrel having awall circling an axis and defining a first lumen, a first channel in thewall having a first slope with respect to the axis and a second channelin the wall having a second slope with respect to the axis and having C2symmetry about the axis with respect to the first slope, (b) a secondblade having attached thereto a second barrel, the second barrel havinga wall circling an axis and defining a second lumen, a third channel inthe second wall having a third slope at a third angle with respect tothe axis, and a fourth channel in the second wall having a fourth slopeat a fourth angle with respect to the axis, the slope of the third anglebeing opposite in sign with respect to the axis to that of the firstangle and the fourth channel having C2 symmetry about the axis withrespect to the third channel, wherein the first barrel fits within thesecond lumen of the second barrel such that the first and third channelsintersect to form a first gap and the second an fourth channelsintersect to form a second gap; (c) a cylindrical plunger having anaxis, an outer surface, a first end and a second end, the first endhaving a hole through and at a right angle to the plunger axis, and thesecond end having a screw thread cut into the surface of the plunger,the cylindrical plunger fitting within the first lumen of the firstbarrel such that said hole aligns with the first gap and the second gapand the hole, first gap and second gap forming a passage; (d) a rodfitting through the passage such that movement of the plunger along theaxis causes the first barrel to rotate in a first direction and thesecond barrel to rotate in a second direction opposite the firstdirection; (e) a holder possessing a third lumen, wherein the secondbarrel fits within the third lumen; and (f) a nut having an internalscrew thread and fitting over the end of the plunger; whereby rotationof the nut causes the internal screw thread of the nut to engage theplunger screw thread and causes the plunger to move along its axis,thereby causing the first and second barrels to rotate about the axis inopposite directions. In some embodiments of the blade assembly the thirdangle is opposite in sign and congruent with the first angle and thefourth angle is opposite in sign and congruent with the second angle. Insome embodiments of the blade assembly at least the first angle has amagnitude with respect to the axis of less than about 75.degree. In someembodiments of the blade assembly, each angle has a magnitude withrespect to the axis of less than about 75.degree. In some embodiments ofthe blade assembly each angle has a magnitude with respect to the axisof about 20.degree. to about 70.degree. In some embodiments of the bladeassembly, each channel has a first end and a second end and the nut andplunger are threaded so that the rod moves from the first end of thechannels to the second end within 1 to 10 full rotations of the nut. Insome embodiments of the blade assembly, the rod moves from the first endto the second end of the channels within 2 to 8 full rotations of thenut. In some embodiments of the blade assembly the rod moves from thefirst end to the second end of the channels within 3 to 6 full rotationsof the nut. In some embodiments of the blade assembly, the rod movesfrom the first end to the second end of the channels within 4 to 6 fullrotations of the nut. In some embodiments of the blade assembly, atleast one blade is comb shaped. In some embodiments of the bladeassembly, both blades are comb shaped. In some embodiments of the bladeassembly, at least one blade is fan shaped. In some embodiments of theblade assembly, both blades are comb shaped. In some embodiments of theblade assembly, the holder is adapted to be removably affixed to an armof a retractor. In some embodiments of the blade assembly, the holder isirreversibly affixed to an arm of a retractor.

Thus, the some embodiments provides a retractor as described herein,wherein at least one blade assembly is a retractor blade assembly,comprising: (a) a first blade having attached thereto a first barrel,the first barrel having a wall circling an axis and defining a firstlumen, a first channel in the wall having a first slope with respect tothe axis and a second channel in the wall having a second slope withrespect to the axis and having C2 symmetry about the axis with respectto the first slope, (b) a second blade having attached thereto a secondbarrel, the second barrel having a wall circling an axis and defining asecond lumen, a third channel in the second wall having a third slope ata third angle with respect to the axis, and a fourth channel in thesecond wall having a fourth slope at a fourth angle with respect to theaxis, the slope of the third angle being opposite in sign with respectto the axis to that of the first angle and the fourth channel having C2symmetry about the axis with respect to the third channel, wherein thefirst barrel fits within the second lumen of the second barrel such thatthe first and third channels intersect to form a first gap and thesecond an fourth channels intersect to form a second gap; (c) acylindrical plunger having an axis, an outer surface, a first end and asecond end, the first end having a hole through and at a right angle tothe plunger axis, and the second end having a screw thread cut into thesurface of the plunger, the cylindrical plunger fitting within the firstlumen of the first barrel such that said hole aligns with the first gapand the second gap and the hole, first gap and second gap forming apassage; (d) a rod fitting through the passage such that movement of theplunger along the axis causes the first barrel to rotate in a firstdirection and the second barrel to rotate in a second direction oppositethe first direction; (e) a holder possessing a third lumen, wherein thesecond barrel fits within the third lumen; and (f) a nut having aninternal screw thread and fitting over the end of the plunger; wherebyrotation of the nut causes the internal screw thread of the nut toengage the plunger screw thread and causes the plunger to move along itsaxis, thereby causing the first and second barrels to rotate about theaxis in opposite directions. In some embodiments, the third angle isopposite in sign and congruent with the first angle and the fourth angleis opposite in sign and congruent with the second angle. In someembodiments, at least the first angle has a magnitude with respect tothe axis of less than about 75.degree. In some embodiments, each anglehas a magnitude with respect to the axis of less than about 75.degree.In some embodiments, each angle has a magnitude with respect to the axisof about 20.degree. to about 70.degree. In some embodiments, eachchannel has a first end and a second end and the nut and plunger arethreaded so that the rod moves from the first end of the channels to thesecond end within 1 to 10 full rotations of the nut. In someembodiments, the rod moves from the first end to the second end of thechannels within 2 to 8 full rotations of the nut. In some embodiments,the rod moves from the first end to the second end of the channelswithin 3 to 6 full rotations of the nut. In some embodiments, the rodmoves from the first end to the second end of the channels within 4 to 6full rotations of the nut. In some embodiments, at least one blade iscomb shaped. In some embodiments, both blades are comb shaped. In someembodiments, at least one blade is fan shaped. In some embodiments, bothblades are comb shaped. In some embodiments, the holder is adapted to beremovably affixed to an arm of a retractor. In some embodiments theholder is irreversibly affixed to an arm of a retractor.

In some embodiments, a kit includes a retractor as described herein,wherein at least one blade assembly comprises: (a) a first blade havingattached thereto a first barrel, the first barrel having a wall circlingan axis and defining a first lumen, a first channel in the wall having afirst slope with respect to the axis and a second channel in the wallhaving a second slope with respect to the axis and having C2 symmetryabout the axis with respect to the first slope; (b) a second bladehaving attached thereto a second barrel, the second barrel having a wallcircling an axis and defining a second lumen, a third channel in thesecond wall having a third slope at a third angle with respect to theaxis, and a fourth channel in the second wall having a fourth slope at afourth angle with respect to the axis, the slope of the third anglebeing opposite in sign with respect to the axis to that of the firstangle and the fourth channel having C2 symmetry about the axis withrespect to the third channel, wherein the first barrel fits within thesecond lumen of the second barrel such that the first and third channelsintersect to form a first gap and the second an fourth channelsintersect to form a second gap; (c) a cylindrical plunger having anaxis, an outer surface, a first end and a second end, the first endhaving a hole through and at a right angle to the plunger axis, and thesecond end having a screw thread cut into the surface of the plunger,the cylindrical plunger fitting within the first lumen of the firstbarrel such that said hole aligns with the first gap and the second gapand the hole, first gap and second gap forming a passage; (d) a rodfitting through the passage such that movement of the plunger along theaxis causes the first barrel to rotate in a first direction and thesecond barrel to rotate in a second direction opposite the firstdirection; (e) a holder possessing a third lumen, wherein the secondbarrel fits within the third lumen; and (f) a nut having an internalscrew thread and fitting over the end of the plunger; whereby rotationof the nut causes the internal screw thread of the nut to engage theplunger screw thread and causes the plunger to move along its axis,thereby causing the first and second barrels to rotate about the axis inopposite directions.

In some embodiments, a method as described herein uses a retractor asdescribed herein, wherein at least one blade assembly is a retractorblade assembly, comprising: (a) a first blade having attached thereto afirst barrel, the first barrel having a wall circling an axis anddefining a first lumen, a first channel in the wall having a first slopewith respect to the axis and a second channel in the wall having asecond slope with respect to the axis and having C2 symmetry about theaxis with respect to the first slope; (b) a second blade having attachedthereto a second barrel, the second barrel having a wall circling anaxis and defining a second lumen, a third channel in the second wallhaving a third slope at a third angle with respect to the axis, and afourth channel in the second wall having a fourth slope at a fourthangle with respect to the axis, the slope of the third angle beingopposite in sign with respect to the axis to that of the first angle andthe fourth channel having C2 symmetry about the axis with respect to thethird channel, wherein the first barrel fits within the second lumen ofthe second barrel such that the first and third channels intersect toform a first gap and the second an fourth channels intersect to form asecond gap; (c) a cylindrical plunger having an axis, an outer surface,a first end and a second end, the first end having a hole through and ata right angle to the plunger axis, and the second end having a screwthread cut into the surface of the plunger, the cylindrical plungerfitting within the first lumen of the first barrel such that said holealigns with the first gap and the second gap and the hole, first gap andsecond gap forming a passage; (d) a rod fitting through the passage suchthat movement of the plunger along the axis causes the first barrel torotate in a first direction and the second barrel to rotate in a seconddirection opposite the first direction; (e) a holder possessing a thirdlumen, wherein the second barrel fits within the third lumen; and (f) anut having an internal screw thread and fitting over the end of theplunger; whereby rotation of the nut causes the internal screw thread ofthe nut to engage the plunger screw thread and causes the plunger tomove along its axis, thereby causing the first and second barrels torotate about the axis in opposite directions.

The embodiments will now be further described with reference to theappended drawings. In FIG. 1 there is shown a perspective view of aretractor 10 according to the present invention. The retractor 10comprises a first arm 12, having a distal end 14 to which is attached afirst blade assembly 16, comprising a first blade 18, a second blade 20and an adjuster 22; a second arm 32, having a distal end 34, to which isattached a second blade assembly 36 comprising a third blade 38, afourth blade 40 and an adjuster 42. The retractor further comprises afirst handle 24 having a distal end 28 and a proximal end 26 and asecond handle 44 comprising a distal end 48 and a proximal end 46. Thetwo handles 24 and 44 are joined to one another by a pivot 50 and arespanned by a biasing spring 52. The retractor 10 further comprises aratchet lock 54, which has serrations 56 that are adapted to engage anengagement member 58, which together with the ratchet lock 54 serves tohold the retractor in a particular position. In FIG. 1, the retractor 10is shown in the “closed” position, meaning that the two blade assemblies16 and 36 are relatively close to one another, as are the two arms 12and 32 and the distal ends 28 and 48 of the handles 24 and 44,respectively. Depression of the proximal ends 26 and 46 of handles 24and 44, respectively, in the directions of the arrows a and b results inthe blade assemblies 16 and 36 moving apart along the directional arrowsc and d, thus causing retractor 10 to assume the configuration depictedin FIG. 2. Note that the directional arrows c and d define a geometricline passing through and joining axis f, which passes vertically throughfirst adjuster 22, and axis g, which passes vertically through secondadjuster 42. Hereinafter axis f may be referred to alternatively as afirst axis, axis g may be referred to alternatively as a second axis andthe axis defined by directional arrows c and d may alternatively bereferred to as a third axis. The importance of these axes will becomeevident upon consideration of the remaining figures.

As can be seen in FIG. 2, the retractor 10 is in an “open” position,meaning that the first blade assembly 16 is relatively separated fromthe second blade assembly 36 along the third axis defined by directionalarrows c and d. Thus, as the blade assembly 16 moves along line d andblade assembly 36 moves along line c they exert force in the directionof lines d and c, respectively. Insertion of the blade assemblies 16 and36 into an incision (not shown) in a closed position (as in FIG. 1) andopening the blade assemblies 16 and 36 to an open position (as in FIG.2) results in a stretching of the incision along the same axis definedby directional lines c and d.

It is noted that in the embodiment depicted in FIGS. 1 and 2, theactuator comprises a pair of arms 12 and 32 and a pair of handles 24 and44. The person skilled in the art will recognize that other embodimentsof an actuator may be used. For example, scissor-like actuators areknown in the clamp and retractor arts. In some such embodiments, theactuator comprises a pair of handles such as those depicted in FIG. 1having attached at the distal ends of the handles 28 and 48 a pair ofblade assemblies 16 and 36 according to the illustrated embodiment.Moreover, while the handles 24 and 44 are depicted as being roughlyparallel and joined together at a pivot point 50, it is also within theskill in the art to use a pair of crossed (e.g. scissor-like) handlesjoined by a pivot. These and other embodiments of actuators are known inthe art and contemplated as being within the scope of some aspects ofthe application. It is also to be understood that when the actuator is ascissor-like embodiment, the motion of blade assemblies 16 and 36traverse an arc rather than a straight line upon opening of theretractor. Nevertheless, the spatial relationship of the two bladeassemblies 16 and 36 can be conceptualized as changing along a linedescribed by arrows c and d, which for the purpose of brevity isreferred to herein as an axis, and in particular the third axis (axes fand g being the first and second axes).

The actuator comprising a pair of arms 12 and 32 and a pair of handles24 and 44 as just described allows movement of both arms 12 and 32 aboutpivot 50 (as illustrated in FIGS. 7 and 8). In some embodiments, themovement of one handle 24 toward the other handle 44 causes outwardmovement of only one arm while the other arm is left entirely fixed ormoves a lessor amount. A retractor 10 system in which actuation of thesystem induces movement of only one arm (or reduced movement) of theretractor 10 can be particularly desirable in situations in which theretractor 10 will be used in close proximity to a delicate or sensitiveanatomy. For example, if a surgeon desires to operate near a crucialnerve, the surgeon can use a retractor 10 with only one movable arm toprotect the nerve by placing the fixed arm next to the nerve. Therefore,upon actuating the retractor 10, only the arm opposite the nerve willmove out to open the surgery site. In such a manner, the surgeon caneffectively protect crucial structures while using the retractor 10herein disclosed to access a nearby surgery site. In operation, theretractor 10 with a fixed arm operated substantially the same as otherembodiments of the retractors 10 herein disclosed. For example, bothsystems can have blade systems 36 and 16 to further expand the surgerysite. Thus, in one arrangement, the retractor can include a said firstblade assembly that movable relative to a fixed second blade assemblyand wherein said first blade assembly is configured to detachablyseparate from said second blade assembly when said retractor is in anopen configuration.

Turning adjuster 22 about axis f in the direction of adjustment arrow h,and adjuster 42 about axis g in the direction of adjustment arrow j,results in opening of the blade assemblies 16 and 36, respectively, asdepicted in FIG. 3. As shown in FIG. 3, opening of the blade assembly 16causes the blade 20 to exert force in the direction of direction arrown, while blade 18 exerts force in the direction of direction arrow p.Likewise, opening of blade assembly 36 causes blade 40 to exert force inthe direction of arrow k, while blade 38 exerts force in the directionof arrow m. Thus, after insertion of the closed blade assemblies 16 and36 of a closed retractor 10 in an incision, opening the retractor 10 andthen opening the blade assemblies 16 and 36, the retractor 10 createsand maintains an aperture in the incised tissue that is both longer(i.e. dimensionally larger in the direction of the incision) and wider(i.e. dimensionally larger in a direction perpendicular or oblique tothe direction of the incision) than the incision. It is to be understoodthat, while this description is especially apt where the incision is astraight line incision of about 0.1 to about 3 inches in length, it canapply to any shape of incision (e.g. an arc, a sinusoid, etc.) of anylength. In particular embodiments of the application, the contemplatedsize of the incision is about 0.5 to 2 inches in length and the bladeassemblies 16 and 36 are appropriately sized so that when the retractor10 is closed the blade assemblies 16 and 36 fit lengthwise within theincision without requiring substantial stretching of the incised tissueprior to opening of the retractor 10. Thus, in some embodiments, theblades 18, 20, 38 and 40 are sized to snugly fit within the incisionwhen the blade assemblies are closed and the retractor is in a closedposition.

FIG. 4 shows the device 10 with handle assembly 2, comprising inter aliathe handles 24 and 44, separated from arm assembly 4, comprising interalia arms 12 and 32. As can be seen in FIG. 4, the distal end 28 ofhandle 24 has a connecting pin 62 that fits within a connecting hole 64on the first arm 12, while the distal end 48 of handle 44 has aconnecting pin 82 that fits within a connecting hole 84 in the arm 32.In the depicted embodiment, the blade assembly 16 is removable from thedistal end 14 of arm 12 and the blade assembly 36 is removable from thedistal end 34 of arm 32. As depicted, the blade assembly 16 can beconnected to the arm 12 by inserting the projection 70 on the proximalend of holder 6 within orifice 68 in the distal end 14 of arm 12.Likewise blade assembly 36 can be connected to arm 32 by inserting theprojection 90 on the proximal end of holder 8 within the orifice 88 inthe distal end 34 of arm 32.

FIG. 5 depicts the arms 12 and 32 of the arm assembly 4 in an openposition. In this position it can be seen that arms 12 and 32 are joinedone to another by a pair of cross members 72 and 92, which are joinedtogether by a cross member pivot 100. The cross member 72 is connectedto arm 32 via a pivot 98 and to arm 12 via a rod 74, which is moveablealong the length of slot 76. Likewise the cross member 92 is connectedto arm 12 via a pivot 78, and to arm 32 via a rod 94, which is moveablealong the length of slot 96. One skilled in the art will recognize thatthe handle assembly 2 may be removed from the arm assembly 4 by removingthe pins 62 and 82 from their respective holes 64 and 84, resulting inthe device 11 depicted in FIG. 12. This may occur at any time, e.g.prior to or during sterilization of the retractor 10 or during asurgical procedure once the retractor 10 has been opened. Removal of thehandle assembly 2 during surgery may afford a member of the surgicalteam greater freedom of motion, an improved field of view or both.

As can be seen in FIGS. 4 and 5, the blade assemblies 16 and 36 can beremoved from the arm assembly 4. One may find it convenient to removethe blade assemblies 16 and 36 in order to expedite sterilization of theblade assemblies 16 and 36 and/or in order to exchange one or both bladeassemblies 16 and 36 for other blade assemblies (e.g. different sizeblades, different configuration of blades, etc.) as discussed in moredetail herein.

FIG. 6 is an exploded view of the retractor 10 with the blade assemblies16 and 36 in an open position. FIG. 7 is a view of retractor 10 fromabove in a closed position. In this view it can be clearly seen that thebiasing spring 52 tends to bias the handles 12 and 32 apart. Also shownin this view are axes z and z′. In some embodiments, the bladeassemblies 16 and 36 are adapted to rotate about the axes z, z′. In someembodiments, these added degrees of freedom permit the blade assemblies16, 36 to be rotated outward so that they are farther apart at the lowerparts of the blades than at the top. This allows the retractor 10 tocreate an even larger aperture without having to open the retractor 10any farther. FIG. 8 shows a top view of the retractor 10 in an openposition. As shown in FIG. 8 the ratchet 54 locks into position to holdthe retractor 10 in an open position. FIG. 9 shows the retractor 10 fromabove with the blade assemblies 16 and 36 in open positions. FIGS. 10and 11 are expanded views of blade assembly 36 in closed (FIG. 10) andopen (FIG. 11) positions.

FIGS. 13-19 depict the assembly of an embodiment of a blade assembly 36,which comprises blades 40 and 38. Starting with FIG. 13, left openingblade subassembly 242 comprises blade 40, which is connected to innerbarrel 244. The blade 40 comprises a plurality of teeth 254 connected toa bridge 252, which in turn is connected to the inner barrel 244 suchthat rotating the inner barrel 244 about axis y to the left (clockwise)results in the teeth 254 also turning to the left (clockwise). The innerbarrel 244 has a slot 246 cut into the upper portion 245 of the innerbarrel 244. Specifically, the upper portion 245 of the inner barrel 244is that portion of the inner barrel 244 above the highest point at whichthe bridge 252 connects to the inner barrel 244. Not shown in this viewis a corresponding slot on the other side of barrel 244, which isdepicted in FIGS. 29 and 30 as slot 247, as discussed in more detailherein. The inner barrel 244 also has a lumen 248 through the innerbarrel 244 and an engagement groove 250 circumscribing the inner barrel244 above the slot 246.

The right opening blade subassembly 202 comprises blade 38 comprisingteeth 214 connected to a bridge 212, which in turn is attached to theouter barrel 204. The outer barrel 204 also possesses a lip 209, whichis a ledge about the lower portion of the barrel 204. The bridge 212 isconnected to the lip 209 such that rotation of the outer barrel 204 tothe right (counterclockwise) about axis y results in the blade 38 alsoturning to the right (counterclockwise) about the axis y. The outerbarrel 204 has a lumen 208 as well as a pair of slots 206, 207 cut intoupper portion 205 of the barrel 204. For the sake of clarity, the upperportion 205 of the outer barrel 204 is that portion of the outer barrel204 above the lip 209. The relationship of the slots 206, 207, 246 and247 are depicted in FIGS. 29-31.

In FIG. 29 there is depicted a side view of barrel outer barrel 204 andinner barrel 244. For purposes of clarity, the barrels 244 and 204 aredepicted without the additional components of the blade sub-assembliesattached, such as the blades. As can be seen in FIG. 29, slot 206penetrates the upper portion 205 of outer barrel 204. Slot 207, shown indotted lines, also penetrates the upper portion 205 of the outer barrel204, albeit on the opposite side of the outer barrel 204. The outerbarrel 204 also has a lip 209, as mentioned above, which is below theupper portion 205 of the outer barrel 204. Slot 246 penetrates the upperportion 245 of inner barrel 244. Slot 247, shown in dotted lines, alsopenetrates the upper portion 245 of the inner barrel 244, albeit on theopposite side of the inner barrel 244. As shown in FIG. 30, the innerbarrel 244 and the outer barrel 204 have a common axis y, which passesvertically through the lumens (not shown) of the barrels 244 and 204.Axis y thus forms a C2 symmetry axis for slots 206 and 207, as well asfor slots 246 and 247. More specifically, slot 206 forms an angle.alpha. with respect to the y axis, whereas the slot 207 forms an angle−.alpha. with respect to the axis y. Viewed from the vantage offered inFIG. 29, these angles .alpha. and −.alpha. have equal magnitude butopposite slope with respect to the axis y. In a like manner, the slot246 forms an angle .beta., with respect to the axis y and the slot 247forms an angle −.beta. with respect to the axis y. Thus slots 206 and207 possess C2 symmetry about the axis y, as rotation of inner barrel244 about the axis y results in slots 246 and 247 equivalently changingplaces, as these slots possess congruent angles with respect to the yaxis and are located 180.degree. about the axis y from one another.Similarly, the slots 246 and 247 possess C2 symmetry about the axis y,as rotation of the slots 246 and 247 about the y results in slots 206and 207 changing places, as these slots are essentially identical withrespect to the y axis. Note that .alpha. and −.beta. have similarorientation as do −.alpha. and .beta. This accounts for the oppositerotation of the barrels 204, 244. Note also that in this embodimentangles .alpha., .beta., −.alpha. and −.beta. are essentially congruent,although in some embodiments of the application it may be desirable for.alpha. and −.alpha. to differ in magnitude from .beta. and −.beta. Oneof skill in the art would recognize that this latter arrangement wouldcause barrels 204 and 244 to rotate at different rates in oppositedirections. Additionally, in the depicted embodiment it is presumed thatthe slots 206 and 207 are of equal length and start and end atessentially the same height as each other. However, it will beunderstood that the length of the slots 206 and 207 may be affectedinter alia by the method used to form such features in the barrel 204(e.g. machining, molding, etc.) and the assignment of C2 symmetry to theslot pair 206, 207 is intended as an illustrative convenience. Morespecifically, it is intended that breaking the strict mathematical C2symmetry of the slots 206, 207 will not affect the operation of theapplication. Likewise breaking the strict mathematical C2 symmetry ofthe slots 246, 247 will not affect operation of the device. Thus,lengthening or shortening one of slots 206 or 207, moving one of theslots 206 or 207 up or down the barrel (along the axis y) or bothchanging the length and the position of one of the slots 206, 207 willnot defeat the purpose of the device. Similarly, lengthening orshortening one of slots 246 or 247, moving one of the slots 246 or 247up or down the barrel (along the axis y) or both changing the length andthe position of one of the slots 246, 247 will not defeat the purpose ofthe device. Thus, for the slot pair 206, 207 to satisfy the C2 symmetryrequirement for the purposes of the present device, it is sufficientthat a portion of the slots 206, 207 satisfy the C2 symmetryrequirement. Likewise, it is sufficient for a portion of the slot pair246, 247 to satisfy the C2 symmetry requirement in order for the slotpair 246, 247 to satisfy the C2 symmetry requirement for the purposes ofthe present device. However, in the currently preferred embodiment, theslot pair 206, 207 possess strict C2 symmetry, as does the slot pair246, 247, within reasonable tolerances (e.g. about +/−2%). It is alsonoted that, while the slots 206, 207, 246 and 247 are depicted as havingconstant slope with respect to the axis y, it is possible and wellwithin the skill in the art for the slots to have serpentine or othercurved slopes with respect to the axis y so long as the C2 symmetryrequirement is satisfied through at least a portion of the slot pairs206, 207 and 246, 247. (FIG. 31 shows the angles .alpha., −.alpha.,.beta. and −.beta. independent of the barrels in order to provide easiervisualization of their relationships to one another.)

FIG. 13 further depicts threaded plunger 260 having a bottom 266 and atop 268. The plunger 260 has a set of screw threads 265 near the top 268and a hole 262 at a right angle to and passing through the y axis. Alsodepicted is a holder 270 comprising a lumen 272 and a projection 274.Additionally there is depicted an adjustment nut (or adjuster) 280having internal threads 286 and two engagement holes 284. Also depictedare a connector pin 292 and two engagement pins 294.

As seen in FIG. 14, the left turning barrel 244 fits within the lumen208 of the right turning barrel 204. The plunger 260 then fits withinthe lumen 248 of the left turning barrel 244, as depicted in FIG. 15. Inthis configuration, the left turning slot 246 crosses the right turningslot 206 forming a passage 261 through which, as depicted in FIG. 16,the connector pin 292 fits. As depicted in FIG. 16, the blades 38 and 40are in a closed position with the connector pin 292 at the bottom of theslots 24. In this configuration, it is seen that the two blades 38, 40interlace to form a substantially planar blade pair, thus rendering theblade pair especially suitable for insertion within a small incision.One skilled in the art will recognize that moving the blades 38 and 40apart will cause the barrels 244 and 204 to rotate in oppositedirections, thereby causing connector pin 292 to rise along slots 246and 206, thereby causing the plunger 260 to rise along the y axis.Conversely, pulling the plunger 260 up along the y axis would cause theconnector pin 292 to rise along the slots 246 and 206, thereby causingthe barrels 244 and 204 to rotate in opposite directions, thus causingthe blades 40 and 38 to move apart. Conversely, starting with theconnector pin 292 at the top of slots 246 and 206, pressing the plunger260 down will cause the connector pin 292 to move down the slots 246 and206, thereby causing the barrels 244 and 204 to rotate in oppositedirections, thereby causing the blades 38 and 40 to rotate toward oneanother. As can be seen in FIG. 17, the assembly of barrel 244, barrel204 and plunger 260 fits through the lumen 272 of the holder 270 so thatthe threads 264 toward the end 268 of the plunger 260 are visible abovethe lumen 272 of the holder 270 and the lip 209 of the outer barrel 204abuts the holder 270. As can be seen in FIG. 18, the adjustment nut(adjuster) 280 fits over the end 268 of the plunger 260 and is held inplace by pushing the engagement pins 294 through the engagement holes284. One of skill in the art will appreciate that the engagement pins294 thus engage the engagement groove 250 on the barrel 244, therebypermitting the adjustment nut 280 to freely turn about the y axis, butpreventing the adjustment nut 280 from moving up or down along the yaxis. The inner threads 286 of the adjustment nut 280 thus engage theouter threads 264 of the plunger 260. Turning the adjustment nut 280about the y axis in one direction causes the plunger 260 to move upwardalong the y axis, while turning the adjustment nut 280 in the oppositedirection causes the plunger 260 to move downward along the y axis. Asexplained above, movement of the plunger 260 causes movement of theconnector pin 292 up and down the y axis. Movement of the pin 260 in onedirection creates force in one direction on the slots in one barrel andin the opposite direction on the slots in the other barrel. Thus, theadjustment nut 280 can be turned to open an close the blade assembly 36.FIG. 19 shows a fully assembled blade assembly 36 in the closedposition.

The blades used in the blade assemblies may have a variety ofconfigurations. FIG. 20 shows an alternate embodiment of a bladeassembly 300 according to the device, which comprises a holder 302connected to a projection 308, which is adapted to reversibly insertinto the end of an actuator arm (not shown). The blade assembly 300further comprises an adjuster 304 and a plunger 306. The adjuster 304 isthreaded on the inside, just as the plunger 306 is threaded on its outersurface, so that turning the adjuster causes the plunger 306 to move upand down. The plunger 306 operates through the holder 302 to turn theblades 320, 330 in opposite directions as described in more detail withregard to FIGS. 1-13 above. In particular, the plunger 306 operates toturn inner barrel 322 in the opposite direction to outer barrel 332essentially as described above. Inner barrel 322 is connected to bridge312 from which project teeth 316. Together bridge 312 and teeth 316 formthe blade 320. Outer barrel 332 is connected to bridge 314 from whichproject teeth 318 and fan 334. Together bridge 314, teeth 318 and fan334 form the blade 330.

Another embodiment of a blade assembly 300 is shown in FIG. 21, wherethe blade 320 comprises fan 338; and blade 330 comprises fan 336. As canbe seen in FIGS. 22-28, blades 320, 330 can have a variety of lengths ofbridges 312, 314, teeth 316, 318, etc. (In these figures, the samenumbering is used as in FIGS. 1-13.

In some embodiments, contemplates kits comprising a retractor. In someembodiments, the kit comprises a single actuator (e.g. a removablehandle and arm assembly as described herein and depicted in the figures,a scissor-like assembly, etc.) and a plurality of removable andexchangeable blade assemblies. In some embodiments, the kit comprises atleast three blade assemblies having amongst the three blade assembliesat least two distinct blade configurations. In other embodiments, thekit comprises from 3 to 12 blade assemblies having amongst the severalblade assemblies from 2 to 12 distinct blade configurations. In someembodiments, the kit comprises at least two pairs of identical orsubstantially similar blade assemblies. In other embodiments, the kitcomprises from 2 to 10, especially about 2 to 5 such pairs of bladeassemblies. The blade configurations that are represented in such kitscan include comb-like blades, interlocking comb-like blades (as depictede.g. in FIGS. 1-12), fan-like blades (as depicted in FIG. 21),combinations of toothed and fan-like blades (as depicted in FIG. 20),etc.

It is noted that in some embodiments the threads 286 and 268 can becanted with respect to the y axis to provide mechanical advantage to theoperator opening and closing the blade assembly 36. In particular, thethreads may be canted so that one full rotation of the nut 280 willresult in the connector pin 292 rising from 1/10 to all the way from itslowest position to its highest position. In some embodiments, the userwill be required to perform from about 1 to about 10 full rotations,especially about 2 to about 8 full rotations, and in particular about 2,3, 4, 5, 6, 7 or 8 full rotations of the nut 280 to cause the connectorpin to traverse the length of the slots 206 and 246, thereby moving theblade assembly 36 from its fully open to its fully closed position orvice versa.

A method according to the an embodiment can be visualized by referringto FIGS. 32-35. In FIG. 32, there is depicted a retractor 10 comprisinga pair of handles 24, 44 and a pair of blade assemblies 16, 36 asdescribed in more detail herein. An incision I having a length L is madein a suitable tissue, such as the skin overlying or in proximity to thelumbar region of the spine. The blade assemblies 16, 36 are in a closedposition and aligned relatively parallel to one another. In FIG. 33, theblade assemblies 16, 36 have been inserted into the incision I. Pressureon handles 24, 44 causes the retractor 10 to open: i.e. blade assemblies16, 36 move apart from one another in the general directions ofdirectional arrows c, d, respectively. As can be seen in FIG. 34, theincision I is stretched open in the direction of the directional arrowsc and d so that it obtains a length L′ greater than length L of theincision. Turning the adjusters 22, 24 in the direction of the curvedarrows about the axes f and g, respectively results in the opening ofthe blade assemblies 16, 36, causing the incision I to open as can beseen in FIG. 35. As can be seen in FIG. 35, the aperture A is openedhaving a length L′ and a width W′. The aperture A thus provides anaccess area of dimensions L′.times.W′ for surgical personnel to view theoperating field, to pass instruments, sutures, implants and othersurgical materials through the aperture. Reversal of the steps outlinedin FIGS. 32-35 results in a final incision I having substantially thesame length L and essentially no width, just as the original incision I.By way of comparison, in order for a prior art device having a pair ofblades to crease such an aperture, the incision I would have to have alength L′ and the blades would have to have a width of L′. Thus, thepresent embodiment permits the use of a much smaller incision to createthe aperture. Thus, the present embodiment permits less invasivesurgical methods, quicker and more comfortable recovery from surgery andpotentially cost savings for the medical coverage provider.

FIGS. 36A-36F illustrate a probe 400 and a method for its use inconjunction with the retractor 10. FIG. 36A illustrates a probe 400 anda portion of a spine, including a first vertebra 440, a second vertebra450, and a disc 460 disposed between the first vertebra 440 and thesecond vertebra 450. The probe 400 can have a probe body 410, a proximalend 413, a distal end 412, an anchor tip 430, and a distal shoulder 420.The anchor tip 430 can be disposed at the distal end 412 of the probebody 410. The distal shoulders 420 can be located at the distal end 412of the probe 400 at the base of the anchor tip 430. In modifiedembodiments, the probe 400 can have a distal end of a different shape.For example, the distal end 412 can be formed without the shoulder 420and/or without the tip 430 and/or one of both elements can be modifiedin shape.

In some embodiments, the probe 400 can be rectangular in horizontalcross section (i.e., the plane bisecting the probe 400 perpendicular tothe axis formed by the proximal end 413 and the distal end 412). Inother embodiments, the probe 400 can be circular in horizontal crosssection or oval cross section. FIG. 38A-38I illustrate somerepresentative cross sectional shape the probe 400 can have, including:a circle (shown in FIG. 38A); an oval (shown in FIG. 38B); a triangle(shown in FIG. 39C); a flattened oval (shown in FIG. 38D); a thinflattened oval (shown in FIG. 38E); a rounded rectangle (shown in FIG.38F); a thin rounded rectangle (shown in FIG. 38G); a rectangle (shownin FIG. 38H); and a thin rectangle (shown in FIG. 38I). In yet otherembodiments, the probe 400 can be any other appropriate shape, includingbut not limited to square, triangular, and ellipsoid. A rectangularcross-sectional shape can include a shape in which the corners of thedevice are rounded and/or arrangements in which the adjacent sides arenot exactly perpendicular (e.g., plus or minus 10 degrees, 5 degrees, 1degrees or 0.1 degrees from perpendicular) and/or when the sides of theprobe have ridges, bends that deviate 10%, 5%, 1% or 0.1% from the widthor length of a side. FIGS. 37A and 37B illustrate a probe 400 withcircular cross section and a probe 400 with an oval cross sectionrespectively.

In some embodiments, the probe 400 can be constructed out of abiocompatible metal, such as but not limited to stainless steel,titanium, and cobalt chrome moly. In other embodiments, the probe 400can be constructed out of a biocompatible ceramic. In still otherembodiments, the probe 400 can be constructed out of any stiff,biocompatible material, including such classes of materials as metals,ceramics, and polymers, or any combinations thereof.

In some embodiments, the probe 400 can have a vertical length (i.e.,length from the distal end 412 to the proximal end 413) in the range ofabout 5-50 cm, about 6-40 cm, about 7-30 cm, about 7-20 cm and about8-10 cm or any other range which is appropriate to allow the probe 400to function as desired. In some embodiments, the probe 400 can have awidth in its largest, non-vertical dimension, in the range of about 5mm-5 cm, about 6 mm-4 cm, about 7 mm-3 cm, and about 8 mm-2 cm,including about 1.5 cm.

In some embodiments, the distal shoulders 420 can extend horizontally infrom the edges of the probe 400 in the range of about 0.1-5 mm, about0.2-4 mm, about 0.3-3 mm, about 0.4-2 mm, about 0.5-1 mm, and about0.6-0.8 mm. In some embodiments, the external corners where the distalshoulders 420 meet the vertical edges of the probe 400 can be squared.In other embodiments, the external corners where the distal shoulders420 meet the vertical edges of the probe 400 can be rounded or smoothed.In some embodiments, the distal shoulders 420 can be machined flat onthe bottom (particularly in such embodiments in which the probe 400 is ashape other than rectangular). In other embodiments, the distalshoulders 420 can be sharpened across their entire length to form ablade along their entire length. In other embodiments, the distalshoulders can be are sharpened across only a portion of their length toform a blade along only a portion of their length. For example, in someembodiments, only half of each distal shoulder 420 is sharpened (e.g.,either the half of the distal shoulders 420 abutting the anchor tip 430or the half of the distal shoulders 420 abutting the edges of the probe400).

In some embodiments, the anchor tip 430 can extend downward from thedistal end 412 of the probe 400. In some embodiments, the anchor tip 430can be substantially triangular (illustrated in FIG. 36A). In otherembodiments, the anchor tip 430 can be substantially parabolic. In otherembodiments, the anchor tip 430 can be a small cylindrical member, suchas a trocar. In yet other embodiments, the anchor tip 430 can be anyshape which allows anchoring of the probe 400 in tissue. In someembodiments, the edges of the anchor tip 430 can be machined to besubstantially smooth. In other embodiments, the edges of the anchor tip430 can be sharpened to form a blade.

In some embodiments, at least a portion of the vertical edges of theprobe 400 can be sharpened. In some of these embodiments, the portion ofthe edges of the probe 400 which are sharpened can be disposed near thedistal end 412 of the probe 400. As a representative example, 1-5 cm ofthe edges of the probe 400 extending up from the distal end 412 anddistal shoulders 420 can be sharpened to form a blade to facilitateinsertion of the probe 400 into corporeal tissue of a patient.

In operation, the probe 400 can be inserted into a patient, preferablyinto an anchorable location, such as a collagenous tissue, bone, orvertebral disc. FIG. 36A illustrates the probe 400 being inserted into apatient (not fully shown) toward the spine (only a first vertebra 440,second vertebra 450, and disc 460 are illustrated in this representativeexample). The probe 400 illustrated in FIG. 36A is a thin, blade likerectangular probe 400 with a triangular anchor tip 430 and squaredcorners where the distal shoulders 420 meet the edges of the probe 400.The structure of the probe 400 can facilitate its passage throughtissues of a patient which can run parallel to the flat surfaces of theprobe. In operation, a physician can select a location in which hedesires to use a retractor 10 to form an operative channel in thetissues of the patient (the spine will be used in this example forillustration purposes only). After the surgeon selects the location forretractor 10 placement, he can insert the probe 400 by placing theanchor tip 430 against the surface of the patient and applying pressureto the proximal end 413. The physician can then continue to applypressure, thereby pushing the probe 400 through the tissue of thepatient, until the probe 400 is fully in place. In some embodiments, animaging modality can be used during the insertion of the probe 400. As arepresentative, non-limiting example, X-ray fluoroscopy can be usedduring insertion of the probe 400 to ensure correct placement. Anyappropriate imaging modality can be used to monitor the placement of theprobe 400. In some embodiments, a surgeon can make an incision withanother instrument, such as a scalpel, prior to the insertion of theprobe 400, into which the probe 400 is inserted.

FIG. 36B illustrates the probe 400 fully in place in a patient. Theprobe 400 has been inserted into the side of the spinal column (heredefined by a first vertebra 440, a second vertebra 450, and the disc 460between them). FIG. 36B illustrates the placement of the probe 400 in alocation in which the anchor tip 430 can anchor the probe 400. As shownin FIG. 36B, the probe 400 has been inserted into the patient until theanchor tip 430 has sunk at least some distance into the disc 460 betweenthe first vertebra 440 and second vertebra 450. The anchor tip 430 hassunk into the disc 460 up until the distal shoulders 420 of the probe400. The distal shoulders 420 serve in this example to limit thepossible insertion depth of the anchor time 430 of the probe 400.

FIG. 36C illustrates a retractor 10 (as disclosed herein) and a placedprobe 400. The retractor 10 has blades as disclosed above which, when intheir close conformation, fit substantially closely around the probe400. The blades of the retractor 10 can be any type of blade asdescribed above, including but not limited to a comb style blade, a fanstyle blade, or a combination style blade.

FIG. 36D illustrates the retractor 10 and placed probe 400 of FIG. 36Cwhere the blades of the retractor 10 in their closed conformation havebeen placed around the probe 400 and slipped down around the probe 400into the channel already formed by the probe 400 in the patient, to thespine. FIG. 36D shows the retractor 10 still in its closed conformationand the blades still in their closed conformation such that the bladessubstantially closely enclose the probe 400. FIG. 36E illustrates thesame retractor 10 of FIG. 36D where the retractor 10 has been engagedand the blades have been deployed (both as have been disclosed fullyabove) to pull open the incision formed by the insertion of the probe400.

FIG. 36F illustrates the retractor 10 and blades in place prepared forphysician access to the desired spinal location wherein the probe 400has been removed for physician access. The probe 400 can allow a surgeonto easily and quickly insert a retractor 10 without cutting an incisionall the way to the surgery site prior to inserting the retractor 10 intothe desired location to access the surgery site. Rather, the surgeon canquickly and easily insert the probe 400 into the desired location,anchor the probe 400 using the anchor tip 430 in the desired location,slip the blades of the retractor 10 around the probe 400, and thensimply slip the retractor 10 into place at which point in time theretractor and blades can be engaged to open up the surgical site and theprobe 400 may be removed.

In one embodiment, the probe 400 comprises at least one electrode,wherein the at least one electrode is capable of stimulating a nerve toprovoke an electromyographic response in the nerve. FIG. 37C illustratesa probe 400 with an electrode 431 disposed at the distal end 412 of theprobe 400 on the anchor tip 430. In some embodiments, only one electrodeis used. In other embodiments, a plurality of electrodes can be used,including about 1-10 electrodes, about 2-8 electrodes, about 3-6electrodes and about 4-5 electrodes. In some embodiments, at least oneelectrode can be disposed on the anchor tip 430. In some embodiments, atleast one electrode can be disposed on the probe body 410. The electrode431 can be allowed to any of the embodiments described herein.

In some embodiments, the probe 400 comprises an endoscope 499, whereinthe endoscope 499 can comprise an imaging element 432 at the distal end412 of the endoscope 499. In some of these embodiments, the endoscope499 can be configured to both allow a surgeon to visualize the placementof the probe 400 as well as allow a surgeon to slide a retractor 10 downover the probe 400 and into place as described herein to create anoperative channel. In some embodiments, the endoscope 499 can include ananchor tip 430. Such an endoscope can be applied to any of theembodiments described herein.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. It should be understoodthat various alternatives to the embodiments of the invention describedherein may be employed in practicing the invention. It is intended thatthe following claims define the scope of the invention and that methodsand structures within the scope of these claims and their equivalents becovered thereby.

What is claimed is:
 1. A retractor comprising: a first arm comprising afirst blade extending along a first longitudinal axis; a first adjusterin mechanical communication with the first blade, the first adjusterconfigured to rotate the first blade about a first rotation axis; asecond arm comprising a second blade extending along a secondlongitudinal axis; a second adjuster in mechanical communication withthe second blade, the second adjuster configured to rotate the secondblade about a second rotation axis; a third blade configured to sliderelative to a probe when the probe is inserted into a patient; and anactuator configured to move the first arm and second arm about atrajectory transverse to the first rotation axis and the second rotationaxis, wherein the movement of the first arm and second arm isindependent of the rotation of the first blade about the first rotationaxis and the rotation of the second blade about the second rotationaxis.
 2. The retractor of claim 1, wherein at least one of the firstblade or the second blade is a flat blade.
 3. The retractor of claim 1,wherein at least one blade is removable.
 4. The retractor of claim 1,wherein the trajectory is perpendicular to the first rotation axis. 5.The retractor of claim 1, wherein the rotation of the first blade aboutthe first rotation axis is independent of the rotation of the secondblade about the second rotation axis.
 6. The retractor of claim 1,further comprising the probe.
 7. The retractor of claim 6, wherein theprobe has a rectangular cross-section.
 8. The retractor of claim 6,wherein the probe comprises at least one electrode.
 9. A retractorcomprising: a first arm comprising a first blade extending along a firstlongitudinal axis; a first adjuster in mechanical communication with thefirst blade, the first adjuster configured to rotate about a singleaxis, the first adjuster configured to rotate the first blade onlyclockwise and counterclockwise about a first rotation axis; a second armcomprising a second blade extending along a second longitudinal axis; asecond adjuster in mechanical communication with the second blade, thesecond adjuster adapted to rotate about a single axis, the secondadjuster configured to rotate the second blade only clockwise andcounterclockwise about a second rotation axis; and an actuatorconfigured to move the first arm and second arm to separate the firstblade and the second blade, wherein the movement of the first arm andsecond arm is independent of the rotation of the first blade and thesecond blade, wherein the retractor is configured to slide relative to aprobe when the probe is inserted into an anchorable location of apatient.
 10. The retractor of claim 9, further comprising a lockingmechanism configured to lock a separated position of the first blade andthe second blade.
 11. The retractor of claim 10, wherein the firstadjuster is configured to be rotated when the separated position islocked.
 12. The retractor of claim 9, wherein the actuator allowsmovement about a pivot.
 13. The retractor of claim 9, wherein theactuator is configured to move the first arm and second arm equally. 14.The retractor of claim 9, further comprising a locking mechanismconfigured to prevent movement of the actuator.
 15. A retractorcomprising: a first arm comprising a first blade extending along a firstlongitudinal axis; a first adjuster in mechanical communication with thefirst blade, the first adjuster configured to rotate the first bladeabout a fixed first rotation axis, the first rotation axis extendinglongitudinally and the first blade extending longitudinally; a secondarm comprising a second blade extending along a second longitudinalaxis; a second adjuster in mechanical communication with the secondblade, the second adjuster adapted to rotate the second blade about afixed second rotation axis, the second rotation axis extendinglongitudinally and the second blade extending longitudinally; and anactuator configured to move the first arm and second arm to separate thefirst blade and the second blade, wherein the retractor is configured toslide along a probe toward a patient.
 16. The retractor of claim 15,wherein the first longitudinal axis and the first rotation axis areoffset.
 17. The retractor of claim 15, wherein the first longitudinalaxis and the first rotation axis are parallel.
 18. The retractor ofclaim 15, wherein the first rotation axis and the second rotation axisare configured to be parallel in a low profile insertion configuration.19. The retractor of claim 15, wherein the first longitudinal axis andthe second longitudinal axis are configured to be parallel in a lowprofile insertion configuration.